Table 1.
Functional description of selected WSN-based ITS traffic safety and law enforcement applications.
| System | Main Purpose * | Data Source | Strategy Upon Data/Danger Detection ** | Strategy Upon Vehicle Detection ** | Data Consumer (Acts or Warn Driver) |
|---|---|---|---|---|---|
| iRoad [11] | Overtaking assistance* | Roadside WSN | 2. Warn upstream nodes of presence of vehicles 3. Send to WAN/IMS |
1. Activation of downstream nodes (upon start of overtaking move) | Smartphones running iRide app, leds on the road |
| Work by Qin et al. [12] | Traffic safety (presence of deers, ice...) | Roadside WSN | 2. Warning upstream nodes, propagation by WSN & VANET | 1. Activation of downstream nodes | Equipped vehicles |
| SNMS [38] | Traffic safety | Roadside WSN | 1. Store in local node | 2. Forward: † (a) VANET (b) mobile WLAN |
Equipped vehicles |
| Work by Weingärtner et al. [14] | Monitoring road condition | Roadway WSN | 1. Store (dangerous) road conditions in neighbor WSN nodes | 2. Forwarding to incoming vehicles, VANET dissemination to distant vehicles & WSN nodes | Equipped vehicles |
| Work by Tripp et al. [33] | Traffic safety | equipped vehicles | 1. Vehicles store information of the road (e.g., photograph of next intersection) | 2. WSN detect vehicles, triggering information interchange with RSU | Equipped vehicles |
| SNTISS [34] | General purpose | Roadside WSN | (a) Static monitoring: report to remote server. (b) Dynamic monitoring (e.g., tracking): share with neighbors for collaboration |
Remote Server | |
| Work by Sung et al. [37] | Collision warning | Roadside/Roadway WSN | – | 1. Collaborative vehicle speed measurement and routing to Base Station | Display near base station warn vehicles moving in the opposite direction |
| DGS [15] | Speed, weather monitoring | Roadside WSN | 2a. Speed: warn/photo 1b. Weather: Report via WAN |
1a. Calculate speed | Speed: VMS, camera Weather: Remote Server |
| S3 [16] | Illegal parking & speed control | 2 Roadway WSN: speed & parking | – | Speed: Collaborative speed measurement Parking: Notify positive detections of vehicles in forbidden area |
Loudspeaker/VMS, camera, infraction reporting to server |
| Work by Festag et al.[40] | Safety (road conditions), post-accident investigation | Roadside WSN | 1. Store dangerous road conditions in WSN | 2. Notification of danger to vehicles, VANET dissemination (only to vehicles) | Equipped vehicles, forensic team with tinyPEDS [98] client |
*
Main purpose of the system considered or the one detailed in the paper, use for other purposes may be feasible.
**:
Order of execution denoted by preceding numbers.
†
Alternative options considered in the paper.